APPROXIMATE SOLUTION FOR STREAMLINES ABOUT A LIFTING ROTOR HAVING UNIFORM LOADING AND OPERATING IN HOVERING OR LOW-SPEED VERTICAL-ASCENT FLIGHT CONDITIONS

摘要

It is shown that the usual,assumption of a uniform vortex cylinder for the wake vortex structure of a uniformly loaded, lifting rotor operating in the hovering or low-speed vertical-ascent flight conditions does not yield useful results for the induced velocities in the region about the periphery of the rotor.nIt is then shown that a more realistic approximation for the low-speed flow patterns can he obtained by adding the stream function for the displacement velocity of a disk and the stream function for a ring source coincident with the rim of the rotor to the stream functions for the uniform vortex cylinder and the free-stream velocity. Equations are derived for the relative strengths of the stream functions that are necessary to satisfy certain selected physical conditions.